A. electrons b. megatrons c. neutrons d. protons

Q: The model shows parts of an atom. What term identifies the parts of the atom labeled with a Y?

A:  You're answer is electrons.

Note that there are 3 parts to an atom. The Protons, Neutrons, and Electrons.

As King Jupiter states, each part have a charge:

The Proton has a positive charge

The Neutron does not have a charge

The Electron has a negative charge

The Protons and Neutrons are located towards the center (in the sphere like), and is compacted together. The electrons, on the other hand, orbits the what is identified as X.

Note: Electrons have a smaller mass than Protons and Neutrons, which means that the gravitational pull of the Protons and Neutrons allow the Electrons to keep inside the atom.

hope this helps

"do a testcross with a homozygous recessive plant."

i think the answer is a.keratin is the pigment responsible for skin color.